Magnet roll having an anisotropic bonded magnet portion containing rare earth-iron-nitrogen magnet powder

Abstract

A magnet roll has a plurality of magnetic poles on a surface with at least one magnetic pole portion being composed of an anisotropic bonded magnet including magnet powder and binder resin. The anisotropic bonded magnet contains R—T—N magnet powder, wherein R is at least one rare earth element including Y, Sm being indispensable, and T is Fe or Fe and Co. The R—T—N magnet powder may also contain inevitable impurities such as C, O and H. The binder resin constitutes 20-70% of the volume of the anisotropic bonded magnet such that the anisotropic bonded magnet have a maximum energy product (BH) max of 10 MGOe or more and a residual magnetization Br of 2800 G or more.

What is claimed is:  
     
       1. A magnet roll having a plurality of magnetic poles on a surface, at least one magnetic pole portion being composed of an anisotropic bonded magnet comprising magnet powder and a binder resin, said anisotropic bonded magnet containing an R—T—N magnet powder, wherein R is at least one rare earth element including Y, Sm being indispensable, T is Fe or Fe and Co, and O and H, inevitable impurities, may be contained, and said binder resin, a volume ratio of said binder resin being 20-70%. 
     
     
       2. The magnet roll according to  claim 1 , wherein said anisotropic bonded magnet has a maximum energy product (BH) max  of 10 MGOe or more and a residual magnetic flux density Br of 2800 G or more. 
     
     
       3. The magnet roll according to  claim 1 , wherein said magnet powder comprises main ingredients having a composition represented by R α T 100−(α+δ) N δ  by atomic %, wherein R is at least one rare earth element including Y, Sm being indispensable, T is Fe or Fe and Co, and α and δ satisfy 5≦α≦18 and 4≦δ≦30, respectively; O and H, inevitable impurities; and C, inevitable impurity, reduced to 5 or less atomic %, outer % based on 100 atomic % of said magnet powder, and has a magnetism-generating phase which is substantially a hard magnetic phase composed of a rhombohedral crystal having a Th 2 Zn 17  structure and/or a hexagonal crystal having a Th 2 Ni 17  structure. 
     
     
       4. The magnet roll according to  claim 1 , wherein said magnet powder comprises main ingredients having a composition represented by R α T 100−(α+β+δ) M β N δ  by atomic %, wherein R is at least one rare earth element including Y, Sm being indispensable, T is Fe or Fe and Co, M is at least one element selected from the group consisting of Al, Ti, V, Cr, Mn, Cu, Ga, Zr, Nb, Mo, Hf, Ta and W, Ti being indispensable, and α, β and δ satisfy 5≦α≦18, 1≦β≦30 and 4≦δ≦30, respectively; O and H, inevitable impurities; and C, inevitable impurity, reduced to or less atomic %, outer % based on 100 atomic % of said magnet powder, and has a magnetism-generating phase which is substantially a hard magnetic phase composed of a rhombohedral crystal having a Th 2 Zn 17  structure and/or a hexagonal crystal having a Th 2 Ni 17  structure. 
     
     
       5. The magnet roll according to  claim 1 , wherein said anisotropic bonded magnet contains ferrite magnet powder. 
     
     
       6. The magnet roll according to  claim 3  or  4 , wherein said magnet powder has an average particle size of 1-10 μm.